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bpf: Support passing args to sock_ops bpf function 

Adds support for passing up to 4 arguments to sock_ops bpf functions. It
reusues the reply union, so the bpf_sock_ops structures are not
increased in size.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Lawrence Brakmo 2018-01-25 16:14:09 -08:00 committed by Alexei Starovoitov
parent b73042b8a2
commit de525be2ca
6 changed files with 42 additions and 10 deletions
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1
include/linux/filter.h
View File

@ -1003,6 +1003,7 @@ struct bpf_sock_ops_kern {
struct sock *sk;
u32 op;
union {
u32 args[4];
u32 reply;
u32 replylong[4];
};

40
include/net/tcp.h
View File

@ -2006,7 +2006,7 @@ void tcp_cleanup_ulp(struct sock *sk);
* program loaded).
*/
#ifdef CONFIG_BPF
static inline int tcp_call_bpf(struct sock *sk, int op)
static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)
{
struct bpf_sock_ops_kern sock_ops;
int ret;
@ -2019,6 +2019,8 @@ static inline int tcp_call_bpf(struct sock *sk, int op)
sock_ops.sk = sk;
sock_ops.op = op;
if (nargs > 0)
memcpy(sock_ops.args, args, nargs * sizeof(*args));
ret = BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops);
if (ret == 0)
@ -2027,18 +2029,46 @@ static inline int tcp_call_bpf(struct sock *sk, int op)
ret = -1;
return ret;
}
static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)
{
u32 args[2] = {arg1, arg2};
return tcp_call_bpf(sk, op, 2, args);
}
static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,
u32 arg3)
{
u32 args[3] = {arg1, arg2, arg3};
return tcp_call_bpf(sk, op, 3, args);
}
#else
static inline int tcp_call_bpf(struct sock *sk, int op)
static inline int tcp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)
{
return -EPERM;
}
static inline int tcp_call_bpf_2arg(struct sock *sk, int op, u32 arg1, u32 arg2)
{
return -EPERM;
}
static inline int tcp_call_bpf_3arg(struct sock *sk, int op, u32 arg1, u32 arg2,
u32 arg3)
{
return -EPERM;
}
#endif
static inline u32 tcp_timeout_init(struct sock *sk)
{
int timeout;
timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT);
timeout = tcp_call_bpf(sk, BPF_SOCK_OPS_TIMEOUT_INIT, 0, NULL);
if (timeout <= 0)
timeout = TCP_TIMEOUT_INIT;
@ -2049,7 +2079,7 @@ static inline u32 tcp_rwnd_init_bpf(struct sock *sk)
{
int rwnd;
rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT);
rwnd = tcp_call_bpf(sk, BPF_SOCK_OPS_RWND_INIT, 0, NULL);
if (rwnd < 0)
rwnd = 0;
@ -2058,7 +2088,7 @@ static inline u32 tcp_rwnd_init_bpf(struct sock *sk)
static inline bool tcp_bpf_ca_needs_ecn(struct sock *sk)
{
return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN) == 1);
return (tcp_call_bpf(sk, BPF_SOCK_OPS_NEEDS_ECN, 0, NULL) == 1);
}
#if IS_ENABLED(CONFIG_SMC)

5
include/uapi/linux/bpf.h
View File

@ -952,8 +952,9 @@ struct bpf_map_info {
struct bpf_sock_ops {
__u32 op;
union {
__u32 reply;
__u32 replylong[4];
__u32 args[4]; /* Optionally passed to bpf program */
__u32 reply; /* Returned by bpf program */
__u32 replylong[4]; /* Optionally returned by bpf prog */
};
__u32 family;
__u32 remote_ip4; /* Stored in network byte order */

2
net/ipv4/tcp.c
View File

@ -463,7 +463,7 @@ void tcp_init_transfer(struct sock *sk, int bpf_op)
tcp_mtup_init(sk);
icsk->icsk_af_ops->rebuild_header(sk);
tcp_init_metrics(sk);
tcp_call_bpf(sk, bpf_op);
tcp_call_bpf(sk, bpf_op, 0, NULL);
tcp_init_congestion_control(sk);
tcp_init_buffer_space(sk);
}

2
net/ipv4/tcp_nv.c
View File

@ -146,7 +146,7 @@ static void tcpnv_init(struct sock *sk)
* within a datacenter, where we have reasonable estimates of
* RTTs
*/
base_rtt = tcp_call_bpf(sk, BPF_SOCK_OPS_BASE_RTT);
base_rtt = tcp_call_bpf(sk, BPF_SOCK_OPS_BASE_RTT, 0, NULL);
if (base_rtt > 0) {
ca->nv_base_rtt = base_rtt;
ca->nv_lower_bound_rtt = (base_rtt * 205) >> 8; /* 80% */

2
net/ipv4/tcp_output.c
View File

@ -3469,7 +3469,7 @@ int tcp_connect(struct sock *sk)
struct sk_buff *buff;
int err;
tcp_call_bpf(sk, BPF_SOCK_OPS_TCP_CONNECT_CB);
tcp_call_bpf(sk, BPF_SOCK_OPS_TCP_CONNECT_CB, 0, NULL);
if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk))
return -EHOSTUNREACH; /* Routing failure or similar. */